Crankshaft for internal combustion engines



.March 19, 1935. H. R. RICARDO l CRANKSHAFT FOR INTERNAL COMBUSTION ENGINES Filed Aril 7, 1954 Patented Mar. 19, 1935 A' I W UNITED STATES PATENT OFFICE CRANKSHAFT Foa INTERNAL ooMBUsTIoN v ENGINES Harry Ralph Ricardo, London, England Application April 7, 1934, Serial No. 719,579 In Great Britain April 26, 1933 17 Claims. (Cl. 1S4-6) This invention relates to crankshafts for inby the centrifugal force due to rotation of the ternal combustion engines and in particular to arcrank pin about the crankshaft axis. rangements for lubricating and cooling the crank- According to a. further feature of the invention shaft of a high speed internal combustion engine. the hollow journal has a passage Which is carried La high speed engines heat tends to be generthrough the Wall of the journal with an opening -5 ated by friction at the crank pin and journal at the inner end of this passage in a part thereof bearings at a greater rate than it can be dissiprojecting into or extending across the bore of pated by conduction along the crankshaft or conthe journal. necting rods. Thus unless some means is pro- In the accompanying drawingl0` ided` for removing the heat, the bearings may Figure 1 is a side elevation partly in section of 10.

reach a temperature which Will impair the lubria crankshaft embodying one construction accordcation or greatly reduce the strength of the White ing tothe invention,

metal and in some cases result in melting of the Figure 2 illustrates in section a part of the bearing. crankshaft shown in Figure 1, but on an enlarged 1?'5v In order to cool the crankshaft bearings, the scale,' 15 crank pins and journals may be made hollow and Figure 3 is a section similar to Figure 2 of an connected by means of passages through the Webs, alternative construction of journal, and cooling liquid being fed through the shaft either Figure 4 is a section on the line IV--IV of Figfrom one end to the other or from the middle to ure 3.

the two ends or vice versa. In the construction illustrated in Figures 1 and 20 VWith such an arrangement air entrained in the 2 the crankshaft comprises end journals A, B liquid tends to be centrifugally separated out rotatable in bearings A1, B1, intermediate jourfrom the liquid and to accumulate at certain nals C rotatable in bearings C1 and crank pins points in the crankshaft so that columns of D rotatable in big end bearings D1 (Figure 2) liquid subject to centrifugal force are out of bal- The journals A, B, C and crank pins D are hol- 25 ance hydraulically and the lack of balance oplow as shown and communicate with each other poses the oW of liquid through the crankshaft, through passages E1 drilled in the crank Webs E. thus necessitating considerable additional pres- The crankshaft thus has a continuous passage sure to force an adequate supply of cooling liquid for lubricant from one end of the shaft through through the crankshaft. the journals and crank pins, to the other end of 30 One object of the invention is to enable a high the shaft. A supply of oil is fed under pressure velocity of liquid iioW to be maintained through by a pump F to one end of the shaft and a lightly the bores of the journals and crank pins so as -to loaded relief valve G is provided at the other increase the cooling effect of the liquid, at the end to impose slight pressure on the bulk supply same time preventing centrifugal separation of for the lubrication of other parts of the engine. 35

Y sludge and suspended solid matter from the With a View to causing the air to flow at a lid'uid, high velocity round the whole internal circum- To this end according tothe invention, a crankference Of each Crank IJl D and thus t0 ensure shaft for an internal combustion engine has a mOYe IltGIlSVe and UlfOlm COClDg andalSO J60 40 hollowcrank pin or journal for the passage of prevent centrifugal separation of sludge ,or solid 40 liquid lubricant and a guide therein which causes matta' fmm the mfhe hollow interior 0f each the liquid to follow a helical path as it oWs loncrank P1 n D 1S urmished Wltlfl a plug D2- The gitudinally through the pin or journal. Convenplgug D2 1S provldedj wlw a hehcauy ananged nb iently lthe pin or journal has in it a. cylindrical D the Clcumfelentlal edge of Whlch 'abuts t the ,inner cylindrical surface of the 45 bore and the guide member ts therein. The latagams 2 ter may be in the form of a helical rib or be a hollow clank pm a Shown the plug D bemg held in position by a grub screw D4 conveniently ochehcauy mbbed member nserted m th? bore cupyingthe threaded outer end of one of the holes Preferably a lubncatmg passage 1S formed necessitated for drilling the passages E1 in the through the wall of the crank pin at that part of crank Webs E Each plug D2 has an axial bore 50 it nearer to the crankshaft axis. The purpose of through Wnioh extends a bolt H for holding this is to prevent an excessive flow of lubricating in position dished conical Washers H1 which ooliquid taking place, Owing t0 Centrifugal force. operate with packing rings H2 to seal the ends With the arrangement mentioned, escape of of the hollow crank pin D. If desired the bolt liquid through the lubricating passage is opposed H and plug D2 may be formed as a single unit. 55

crank pin D to allow a small proportion of oil flowing through the hollow pin to pass to the bearings D1. In this way lubrication is provided for the outer bearing surface of each crank pin but, as will be seen from Figure 2, since each lubricating passage D is provided in that part of the crank pin D nearest to the crank axis, the oil pressure in each passage D5 due to centrifugal force is small. Further the parts of the helical passage formed between helices of the rib D3 are in communication with each other through openings D5 cut in the helices D3 at those parts nearest to the crank axis. In this way the formation of air locks in those parts of the helical passage nearest to the crankshaft axis tends to be prevented.

The pump F delivers lubricant to an annular chamber A2 formed in the bearing A1 and from which lubricant can flow through'a feed pipe A3 and a pressure relief valve (not shown) to other parts of the engine including the cam shaft. The liquid lubricant flows from the annular chamber A2 radially inwards through lubricating passages A4, extending radially through the wall of the journal A, into the interior or" the journal to the passage El in the adjacent web E and thence through the associated crank pin D. The helical rib D3 causes the lubricant to low at high velocity around the whole interior surface of the crank pin D and thus ensures efcient cooling. Furthermore the helical path followed by the oil in passing through the crank pin tends to prevent centrifugal separation of sludge or solid matter from the lubricant.

With a view to ensuring that the oil fed to each journal bearing A1, B1, C1 is taken from the inner part of the space within the journal from which any suspended matter will have been removed centrifugally, and also to vent any air which may have become entrained with the oil, each journal is furnished with two oppositely arranged passages which receive the two ends of a tube as shown at C2 (Figure 2) with an opening or openings C3 at or about the centre of the length of the tube C2, that is to say on or near the axis of the crank shaft. The outer ends of the tube C2 communicate with an annular space C formed between the journal C and the bearing C1. The ends of each journal C are closed by conical washers C5 held in position by a pin C5 past which the tube C2 extends. Alternatively the pin C6 may be slightly bent or kinked to allow the tube C2 to pass diametrically across the interior of the journal thus bringing the opening or openings C3 nearer to the axis of rotation. In this way since sediment or solid matter will tend to be maintained near the inner surface of the hollow journal, that is to say at parts more remote from the opening C3, clean oil only will iiow to the annular space C4. In addition air, which if present will tend to collect at the centre of rotation, will be vented through the pipe C2.

Instead of a pipe extending right across the interior of the journal as described with reference to Figure 2, one or more short pipes or hollow bosses may project into the journal either radially or obliquely, the opening at the inner end of each pipe or hollow boss lying near the centre of rotation of the journal. This arrangement is particularly suitable when the central portion of the journal is occupied by a bolt such as the bolt C6 or when, as may be the case, the journal is furnished with a helical plug as described with reference to the crank pin D. Thus,

A passage D5 is provided in the wall of each `lustrated for example in Figures 3 and 4, a

hollow journal J rotatable within a bearing J1 is furnished with a helical plug J2 through which passes a bolt K whereby conical washers K1 are held in position to seal the ends of the hollow journal. If desired the bolt K and plug J2 may be formed as a unit. A lubricating tube L p asses through one wall of the journal and opens at its inner end near the plug J2, that is to say at a substantial distance from the inner surface of the journal J through which the tube L passes. The lubricant ilowing from the passage El in one of the adjacent crank webs E thus iows at a high velocity around the whole interior surface of the journal while the tendency for sludge or solid mattei' which has been centrifugally separated to settle within the journal, is prevented. Furthermore, clean oil only will pass through the lubricating tube L whilst air will also be vented from the interior of the journal.

Since with the construction as above described the quantity or lubricant from the crank shaft which passes to and has a cooling eiect on the engine pistons will tend to be reduced, it may be desirable, where the persent invention is applied to engines of large size and/or subject to high continuous duty, to provide a supplementary supply of lubricant as for instance by causing oil jets to play externally on the big end bearings, or in any other way which will result in this supplementary lubricant reaching the inside of the pistons in the form of inist or spray. The quantity of supplementary lubricant supplied to the pistons may be varied approximately in accordance with Variations in the load on the engine.

It will be understood that the constructions above described are given by way of example only and that details may be modified. For example, the oil, instead of being fed to one end of the hollow crankshaft, may be fed to a point in the length thereof and a relief valve provided at each end. Further, instead of the helical guides being constituted by solid plugs any other suitable arrangement may be employed such, for example, as a hollow helix, resembling a. helical spring and arranged on or near the inner surface of the bore of the journal or crank pin. When a lubricating pipe is provided across the bore of the journal the pipe need not extend diametrically across the bore but may extend on a chord across the interior of the journal, as, for example, in those cases where a bolt lies on the axis of 'the bore of the journal. Instead of providing a short pipe extending radially into the bore of the journal, this pipe may project in a direction oblique to the axis but having a component towards it. Whilst it is preferred to employ a short pipe with this construction it will be understood that a short inwardly projecting boss may be formed on the interior of the journal, such boss having a bore leading through the wall of the journal.

Though in the constructions above described a helical guide and lubricating passage have been provided for intermediate journals any or all of the journals, including the main or end journals, may be provided with helical guides or lubricating tubes or with both helical guides and lubricating tubes.

What I claim as my invention and desire to secure by Letters Patent s:-

1. A crank shaft for an internal combustion engine including in combination at least one hollow journal through which liquid lubricant can flow longitudinally, and means within the journal whereby theliquid is caused to follow a helical path as itflows longitudinally through and within the hollow journal. i

v2.'A fcrank shaft for an internal combustion engine including in combination at least one hollow journal through which liquid lubricant can owlongitudinally, and a guide member within thehollow journal, said vguide member causing the liquidto follow a helical path as the liquid ows longitudinally through and within the hollow journal. A

3. A crank shaft for an internal combustion engine including in combination at least one hollow journal through which liquid lubricant can flow longitudinally, and helically arranged guide surfaces within the journal whereby the liquid is caused to follow a helical path as it flows longitudinally through and within the hollow journal.

4. A crank shaft for an internal combustion engine including in co-mbination at least onehollow journal having a cylindrical bore through which liquid. lubricant can flow longitudinally, a guide plug arranged within the bore, and helically arranged guide surfaces on the guide plug whereby the liquid is caused to follow a helical path as it flows longitudinally through and within the hollow journal.

5. A crank shaft for an internal combustion engine including in combination `at least one hollow journal having a cylindrical bore through which liquid lubricant can flow longitudinally, a guide plug arranged within the bore, and a helical rib on the outer surface of the guide plug whereby the liquid is caused to follow a helical path as it flows longitudinally through and within the hollow journal.

6. A crank shaft for an internal combustion engine including in combination at least one hollow crank-pin through which liquid lubricant can iiow longitudinally, and means within the crank-pin whereby the liquid is caused to follow a helical path as it flows longitudinally through and. within the` hollow crank-pin.

'7. A crank shaft for an internal combustion engine including in combination at least one hollow crank-pin through which liquid lubricant can flow longitudinally, and a guide member with'- in the hollow crank-pin, said guide member causing the liquid to follow a helical path as the liquid flows longitudinally through and within the hollow crank-pin. Y

8. A crank shaft for an internal combustion engine including in combination at least one hollow crank-pin through which Yliquid lubricant can flow longitudinally, and helically arranged guide surfaces within the crank-pin whereby the liquid is caused to follow a helical path as it flows longitudinally through and. within the hollow crankin. p 9. A crank shaft for an internal combustion engine including in combination at least one hollow crank-pin having a cylindrical bore through which liquid lubricant can flow longitudinally, a guide plug arranged within the bore, and helically arranged guide surfaces on the guide plug whereby the liquid is caused to follow a helical path as it flows longitudinally through and within the hollow crank-pin.

10. A crank shaft for an internal combustion engine including in combination at least one hollow crank-pin having a cylindrical bore through which liquid lubricant can flow longitudinally, a guide plug arranged within the bore, and a'helical rib on Vthe outer surface of the guide plug whereby the` liquid is caused to follow a helical path as it flows longitudinally through and within the hollow crank-pin. i

11. A crank shaft for an Vinternal combustion engine including in combination at least one hollow crank-pin through which liquid lubricant can flow longitudinally, means within theY hollow'- crank-pin whereby the liquid -is caused'to `followa helical path as it flows longitudinally through the pin, and at least one passage through which liquid' can iiow direct through and within the interior of the crank-pin at that part of the inner surface thereof which lies nearest to the axis of the crank shaft.

12. A crank shaft for an internal combustion engine including in combination at least one hollow crank-pin having a cylindrical bore through which liquid lubricant can flow longitudinally, a guide plug arranged within the bore, a helical rib on the outer surface of the guide plug whereby liquid is caused to vfollow a helical pathw`- as it flows longitudinally through and within the hollow crank-pin, `and at least one passage adjacent to the outer edges of the helical rib through which passage lubricant can flow direct longitudinally through the crank-pin.

13. A crank shaft for an internal combustion engine including in combination at least one hollow journal through which liquid lubricant can flow longitudinally, means within the journal whereby the liquid is caused to follow a helical path as it flows longitudinally through the hollow journal, at least one hollow crank-pin through which liquid lubricant can flow longitudinally, and means within the crank-pin whereby the liquid is caused to follow a helical path as it flows longitudinally through and within the hollow crank pin.

14. A crank shaft for an internal combustion engine including in combination at least one hollow journal having a cylindrical bore through which liquid lubricant can flow longitudinally, a guide plug arranged within the bore, helically arranged guide surfaces on the guide plug where.- by the liquid is caused to follow a helical path as it flows longitudinally through the hollow journal, at least one hollow crank-pin having a cylindrical bore through which liquid lubricant can flow longitudinally, a guide plug arranged within the bore of the crank-pin, and helically arranged guide surfaces on the guide plug whereby the liquid is caused to follow a helical path as it flows longitudinally through and within the hollow crank-pin.

l5. A crankshaft for an internal combustion engine including in combination at least one hollow journal through which liquid lubricant can flow longitudinally, and a guide member within the journal whereby the liquid lubricant is caused to follow a helical path as it iiows through and within the journal, said journal having a lubrieating passage passing through the wall thereof with the opening at the inner end of said passage lying at a substantial distance from the inner surface of the journal.

16. A crankshaft for an internal combustion engine including in combination at least one hollow journal through which liquid lubricant can now longitudinally, a guide plug arranged within the journal, helical ribs on the guide plug whereby the liquid lubricant is caused to follow a helical path as it flows through and within the journal, a part carried by said journal and projecting into the interior thereof, said inwardly projectjournal, detachable members for' sealing the two. ends of the hollow journal; `a boltV extending through the hollow guide plug and retainingsald' sealing members in position, a part carried by y the journal and yprojecting into -therinterior thereof, 'said inwardly projecting part. havinga lubricating'passage which passes lthrough'-, the

Wall of the journal with the opening at the'izmer. y v end of the lubricating passage lying adjacent to the outer surface of the plug between the helical ribs. v Y

HARRY RALPH RICARDO. Y' 

